Dementia

Dementia is an umbrella of symptoms related to a decline in mental abilities, including thinking, judgment and memory.

It affects about 75,000 people in Orange County, according to UC Irvine's Institute for Memory Impairments and Neurological Disorders.

Alzheimer's disease is the most common type of dementia, making up about 60 percent of cases.

For UC Irvine's 90+ Study, researchers started with a 1981 USC study of Leisure World retirement community residents in Laguna Woods. About 14,000 people ages 55 to 105 filled out a lengthy questionnaire, answering questions related to exercise, diet, surgeries, lifestyle and other things.

The 90+ Study began in July 2003. Over the past decade, UCI researchers have studied 1,600 of the Leisure World residents. New participants are added to the study each year from the original 14,000 participants of the Leisure World Cohort Study.

Why is dementia strongly associated with age? Why is it associated with low blood pressure for people in their 90s? What are the risk factors for dementia?

UC Irvine professor and geriatric neurologist Claudia Kawas has hunches, and she expects her ongoing study of people who are 90 and older will provide some concrete answers.

The National Institute on Aging recently renewed Kawas' 90+ Study with another five-year $9.5 million grant, for a total of 15 years and $30 million.

Winning a federal grant is a competitive process and has become more so under federal budget cuts.

Applications for grants are accepted based on “whether we think the science is important enough,” said Dallas Anderson, program administrator for the National Institute on Aging's Dementias of Aging Branch.

Applications for grants more than $500,000 in any given year go through a rigorous review process.

The 90+ Study has been fruitful, Anderson said. Some of the findings:

 More than 40 percent of people 90 and older have dementia.

 Overweight people in their 70s live longer than normal or under-weight people.

 People who drink moderate amounts of alcohol or coffee live longer than those who abstain.

Kawas notes that many people misunderstand these findings. For example, a 40-year-old person might look at the findings and conclude that it's OK to be overweight. It's not. “Age matters,” she said.

It's unhealthy to be overweight in younger years, but for the over 70 crowd, it is associated with a longer life. And, what's good for someone at age 50, 60 and 70 might not be the same when someone is 90 or 100, Kawas said. “It's bad to lose weight when you're aging.”

Kawas said the same might be true for blood pressure. High blood pressure is bad for younger people, but the optimal blood pressure for a younger person might not be the same for people in their 90s.

People in their 90s may have clogged and narrow blood vessels. They may have the problem of not getting enough blood through the vessels to the brain, Kawas said. If blood pressure is too low, it could cause microinfarction, which are strokes so tiny you can only see them under a microscope. Infarction is when the blood supply to an organ or tissue is cut off, resulting in deterioration of tissue.

Kawas said accumulated microinfarctions could lead to dementia. Older people might be healthier with higher blood pressure.

The 90+ Study is unique, Anderson said.

Most of the dementia studies look at people who are 65 and older. The UCI study examines the lifestyles and brains and, going forward, the DNA of people who are 90 and older for clues to who gets dementia and how it progresses.

The key to understanding dementia is to study it at the extremes – in the oldest people and in the youngest, Anderson said.

People older than 90 aren't an easy population to study because they may have hearing, sight, mobility or other problems that make it difficult for them to participate, Anderson said. Another challenge is tracking the participants. As they get older, some of them move to be closer to relatives.

“That's created a logistical problem for Claudia, too,” Anderson said. “That's part of the cost and part of the energy demand on the team.”

The 90+ Study has already found clues to possibly preventing or treating dementia.

“We hope that we can do something in our lives to postpone or prevent this awful disease,” Anderson said. “There are reasons to be encouraged.”

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